1. Field of the Invention
The present invention relates to a toner cartridge adapted to be detachably attached to a development device of an image forming apparatus so as to supply toner to the development device.
2. Description of the Related Art
Heretofore, there has been known a toner cartridge for use in an image forming apparatus which is designed to form and output an image based on image information obtained through a read operation in a scanner device or transmitted from other apparatus. In the image forming apparatus, this toner cartridge serves as a means to supply toner to a development device for providing toner onto a peripheral surface of a photosensitive drum having an electrostatic latent image formed thereon in accordance with the image information, so as to form a toner image. The toner cartridge is designed to be detachably attached to the development device.
The toner cartridge includes a shutter member for openably closing a toner supply port formed in a bottom wall of a box-shaped cartridge body. Specifically, the toner cartridge is designed such that, when an operator manually opens the shutter member after attaching the toner cartridge to the development device, toner contained in the cartridge body is supplied to the development device through the toner supply port.
In this conventional toner cartridge, the shutter member is likely to be erroneously moved and opened before the toner cartridge is attached to the development device. This causes a problem about occurrence of contamination in the surrounding due to toner scattered outside through the toner supply port. Moreover, during an operation for replacing the toner cartridge, if the cartridge is detached from the development device without closing the shutter member, toner remaining in the cartridge body will be discharged outside to cause the same problem.
As measures against the above problem, a toner cartridge as disclosed in Japanese Patent Laid-Open Publication No. 2004-205587 has been proposed. This toner cartridge includes a lock mechanism for locking an open movement of the shutter member. Specifically, the lock mechanism is designed to allow the shutter member to be locked and kept from being opened when the toner cartridge is not attached to the development device, and to be opened when the toner cartridge is attached to the development device.
Thus, the toner cartridge disclosed in the Japanese Patent Laid-Open Publication No. 2004-205587 makes it possible to eliminate the risk that the shutter member is opened before the toner cartridge is attached to the development device and after it is detached from the development device, so as to reliably prevent the problem about occurrence of contamination in the surrounding due to toner scattered outside from the toner supply port.
In the toner cartridge disclosed in the Japanese Patent Laid-Open Publication No. 2004-205587, the shutter member and a manual operation lever for manually opening and closing the shutter member are connected to one another through a pair of gears formed in them, respectively. Thus, a structure for opening and closing the toner supply port becomes complicated. Moreover, the lock mechanism also has a complicated structure because a single-purpose member separated from the cartridge body is employed to construct the lock mechanism. These structures are likely to cause increases the number of components and man-hours of an assembling process generally more than ever before, resulting in sharp increase in production cost.